Chondrodystrophy results in predictable and progressive biochemical and structural changes to the intervertebral disc, resulting in early onset degeneration and dystrophic mineralization of the disc. Accelerated degeneration and mineralization of the intervertebral disc are common in multiple dog breeds and can result in compromised function, herniation, pain, and a variety of neurological sequelae. A mutation responsible for chondrodystrophy in dogs has been identified as an aberrant fibroblast growth factor 4 (FGF4) retrogene insertion on chromosome 12 (CFA12) and is associated with short stature of the Nova Scotia Duck Tolling Retriever. Segregation of the CFA12 FGF4 retrogene in this dog breed provides an opportunity to examine the effect of retrogene presence on radiographic and histologic appearance of chondrodystrophic disc degeneration within a single breed. Here we found that in the intervertebral discs isolated from 2 dogs with the CFA12 FGF4 genotype, the nucleus pulposus was largely replaced by cartilaginous tissue, and physaliferous notochordal cells were rarely if ever identified. These findings are in contrast to the normal histologic findings in 2 breed-matched dogs lacking the mutation. The findings are consistent with premature chondroid degeneration of the intervertebral disc and suggest that the presence of the CFA12 FGF4 retrogene is sufficient to cause the chondrodystrophic phenotype.

中文翻译：

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年轻新斯科舍省鸭收费猎犬的椎间盘病理特征证实与基因型相关的软骨营养不良的退化表型。

软骨营养不良导致椎间盘的可预测和进行性生化和结构变化，从而导致椎间盘的早发变性和营养不良矿化。加速的椎间盘退变和矿化在多种犬种中很常见，并可能导致功能受损，椎间盘突出，疼痛和各种神经系统后遗症。已将导致犬软骨营养不良的突变鉴定为12号染色体（CFA12）上异常的成纤维细胞生长因子4（FGF4）逆转录基因插入，并与新斯科舍省鸭收费猎犬的矮小身材有关。该犬种中CFA12 FGF4逆转录酶的分离提供了一个机会，可以检查逆转录基因的存在对单个犬种中软骨营养不良性椎间盘退变的放射学和组织学外观的影响。在这里，我们发现在从两只具有CFA12 FGF4基因型的狗中分离出的椎间盘中，髓核在很大程度上被软骨组织所取代，并且即使有过鉴定，很少会发现植骨的脊索细胞。这些发现与2只缺乏突变的品种匹配的狗的正常组织学发现相反。这些发现与椎间盘的软骨早变性有关，并表明CFA12 FGF4逆基因的存在足以引起软骨营养不良的表型。在这里，我们发现在从两只具有CFA12 FGF4基因型的狗中分离出的椎间盘中，髓核在很大程度上被软骨组织所取代，并且即使有过鉴定，很少会发现植骨的脊索细胞。这些发现与2只缺乏突变的品种匹配的狗的正常组织学发现相反。这些发现与椎间盘的软骨早变性有关，并表明CFA12 FGF4逆基因的存在足以引起软骨营养不良的表型。在这里，我们发现在从两只具有CFA12 FGF4基因型的狗中分离出的椎间盘中，髓核在很大程度上被软骨组织所取代，并且即使有过鉴定，很少会发现植骨的脊索细胞。这些发现与2只缺乏突变的品种匹配的狗的正常组织学发现相反。这些发现与椎间盘的软骨早变性有关，并表明CFA12 FGF4逆基因的存在足以引起软骨营养不良的表型。